his species
of marble. Probably the most beautiful of all the ancient breccias is
that called Breccia della Villa Adriana, from its occasional
occurrence in the ruins of Hadrian's Villa, and also Breccia
Quintilina, from its having been found in the grounds of the
magnificent Villa of Quintilius Varus, commemorated by Horace, at
Tivoli, now occupied by the Church of the Madonna di Quintigliolo. The
prevailing colour of the fragments is that of a dark brown intermixed
with others of smaller size, of red, green, blue, white, purple,
bright yellow, and sometimes black, all harmonising together most
beautifully. The comparatively small pieces found at Tivoli now adorn
the Churches of St. Andrea della Valle, famous for its rich varieties
of breccias, St. Domenico e Sisto and Santa Pudenziana, where they
appear among the marble sheathing of the walls. In the chapel of the
Gaetani in the last-mentioned church, the wall is incrusted with the
richest marbles, especially Lumachella and Brocatello, and large
tablets of Hadrian's breccia setting off the splendid sarcophagus of
Breccia nera e gialla dedicated to Cardinal Gaetani.

Along with the breccias which I have thus incidentally noticed, but to
which a whole essay might be devoted on account of their beauty, rich
variety, and great value and rarity, should be classified a kind of
"breccia dure," called Breccia d' Egitto. It is not, however, a true
breccia, but a pudding-stone, composed, not of calcareous but of
siliceous fragments; and these fragments are not angular, as in the
true breccias, but rounded, indicating that they had been carried by
water and consequently rounded by attrition. The connected pebbles
must have been broken from rocks of great hardness to have withstood
the effects of constant abrasion. In the Egyptian breccia are found
very fine pebbles of red granite, porphyry of a darker or lighter
green, and yellow quartz, held together by a cement of compact
felspar. It has a special geological interest, inasmuch as it
represents an ancient sea-beach flanking the crystalline rocks of
Upper Egypt, where the cretaceous and nummulitic limestones end. The
pebbles were derived from the central nucleus of granite from beyond
Assouan to the upper end of the Red Sea, round which are folded
successive zones of gneiss and schist pierced by intrusive masses of
porphyry and serpentine. The pair of beautiful Grecian Ionic columns,
and the large green tazza--eighteen feet in